Ocular drug delivery system

5 October 2016 1
Presented by-
Sangram M.Patil
M.Pharm.
Department of Pharmaceutics

 Introduction
 Human eye anatomy
 Mechanism of ocular absorption
 Factors affecting Intraocular bioavailability
 ophthalmic preparation and classification of Ophthalmic dosage
forms
 Ocular control release system
 Recent formulation trends in OCDDS
 Bibliography
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 Ocular administration of drug is primarily associated with the need to treat
ophthalmic diseases.
 Eye is the most easily accessible site for topical administration of a
medication.
 Ideal ophthalmic drug delivery must be able to sustain the drug release and
to remain in the vicinity of front of the eye for prolong period of time.
COMPOSITION OF EYE:
Water - 98%, Solid -1.8%,
Organic element – Protein - 0.67%,
Sugar-0.65%, NaCl-0.66%
Other mineral element sodium,
potassium and ammonia - 0.79%
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•Structure comprises Three layer-
1)Outer coat- Sclera
2)Middle layer- Choroid
3)Inner layer- Retina
 Lacrimal fluid secreted by
lacrimal gland is emptied on the
surface of the conjunctiva of the
upper eye lid at a turnover rate 16 %
per min.
 The lacrimal fluid volume in
human is 7µl and is an isotonic
aqueous solution of bicarbonate and
sodium chloride of pH 7.4.
The pre-corneal constraints that
are responsible for poor
bioavailability of conventional
ophthalmic dosage form

Non- corneal absorption:
 Penetration across sclera & conjunctiva into intraocular tissues.
 Non productive: because penetrated drug is absorbed by general
circulation.
Corneal absorption:
 Outer epithelium: rate limiting barrier, with pore size 60a, only
access to small ionic and lipophilic molecules.
 Trans cellular transport: transport between corneal epithelium and
stroma.
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1. Inflow & outflow of lacrimal fluids.
2. Efficient naso-lacrimal drainage.
3. Interaction of drug with proteins of lacrimal fluid.
4. dilution with tears.
5. Corneal barriers.
6. Active ion transport at cornea
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OCULAR DISORDER
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Periocular diseases Intraocular diseases
Conjuctivitis Dry eyeKeratitis Iritis Glaucoma
Inflamation
of conjunctiva
Inflamation
of cornea.
Pain and
inflammation
of eye
Inadequate
wetting of
eye
 Build up
pressure in the
anterior and
posterior chamber
of choroid layer
that occur when
aqueous humour
fail drain property.

 Ophthalmic preparations are sterile products that are intended
to be applied topically to cornea or instilled in the space
between the eyeball and lower eyelid.
Conventional ocular formulations for ocular drug delivery:
1. Solutions
2. Suspensions
3. Ointments
4. Gels
5. Emulsions
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1.Ocusert:
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Rate controlling membrane
Annular ring
Pilocarpine reservoir
Rate controlling membrane
 In ocusert the drug reservoir is a thin disc of
pilocarpine- alginate complex sandwiched
between two transparent discs of micro porous
membrane fabricated from ethylene-vinyl
acetate copolymer.
The micro porous membrane permit the tear
fluid to penetrate into the drug reservoir
compartment to dissolve drug from the
complex.

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 Pre-soaked Hydrophilic lenses used.
 Alternative approach- Incorporate drug either
as soln or suspension of solid monomer mixturet hen
polymerization is carried out to fabricate contact
lenses.
 Release rate is up to : 180 hr. as compared to pre-
soaked contact lenses.

1.Lacrisert:
 Sterile, Rod Shaped device made up of Hydroxy
propyl cellulose without preservative.
 Weight:5mg,
 Dimension:Diameter:12.5mm, Length:3.5mm
 Use:-Dry eye treatment, Keratitis
2.SODI: Soluble Ocular Drug Insert
 Sterile thin film of oval shape made from Acryl amide, VinylPyrolidone,
Ethylacrylate.It is used in the treatment of glaucoma and trachoma.
 Inserted into cul-de-sac and get wets and soften in 10-15sec.
 After 10-15min. The film turn into viscous polymer mass.
 After 30-60min.it turn into polymer solution and deliver drug for about 24hr.
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 It is made up of counter disc with Convex front & Concave back surface in
contact with eye ball.
 4-5mm in diameter.
 Composition : Silicon based polymer.
 Mini disc can be Hydrophilic or Hydrophobic to permit extend release of
both water soluble and insoluble drug.
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 This approach for mainly for water soluble drug.
 Particulate drug delivery system 10-1000nm in size in which the drug may be
dispersed, encapsulated or absorbed.
 Produced by emulsion polymerization .In this process poorly soluble soluble
monomer is dissolved the continous phase which may be aqueous or organic.
Polymerization is started by chemical irradiation.
 Emulsifier stabilize resulting polymer solution.
 Material used –Polyalkylcynoacrylate
 Kept the pH below 3 of polymerization medium .After polymerization pH is adjusted
to desired value.
 Biodegradable polymer used. Drug may be added before ,during, after the
polymerization

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 The main advantage of vesicular system is to achieve the control of the rate
of encapsulated drug and protection of the drug from metabolic enzyme
present at the tear corneal epithelium interface.
 Vesicle composed of lipid membrane enclosing an aqueous volume.
 Lipophilic drug drug are delivered greater extent.
 The main drawback of vesicular system is short shelf life, Limited loading
capacity .
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1. Polymeric solutions
2. Phase transition systems
3. Bioadhesive dosage forms
4. Collagen shields
5. Pseudolatices
6. Ocular Iontophoresis
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 Increases tear viscosity
 Decreases rapid initial drainage rate
 Increases corneal contact time
 Increases the corneal penetration of drug
 Polymer used-HPMC, PVP, Chitosan
2) Phase transition systems
 Temperature dependent phase transition system e.g. Lutrol FC 127 and
Poloxamer 407.
 Ion activated system gelrite - An ion activated in situ gelling polymer forms
a clear gel in the presence of cation. e.g. Calcium or sodium ions present in
the tears increase the corneal residence time & bioavailability of drugs.
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 Collagen is the structural protein of bones, tendons, ligaments,
& skin and comprises more than 25% of the total body
weight.
 Collagen shields belong to soluble ophthalmic inserts
manufactured from Procine scleral tissue
 Cross linked collagen shields might be useful in ocular drug
delivery devices because they can allow drug concentrations to
achieve higher levels in cornea & aqueous humor.
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 Organic solution of polymers is dispersed in an aqueous phase
to form O/W emulsion
 Water is removed partially to an extent that residual water is
removed sufficient enough to keep polymeric phase discrete &
dispersed
 On application leave an intact noninvasive continuous
polymer film which reserves drugs
 Drug released slowly over prolonged period of time , better
ocular bioavailability patient compliance
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 It is the process in which the direct current drives ions into cells or
tissues.
 Antibiotics, antifungal, anesthetics and adrenergic are delivered by
this method.
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 Any polymer solution or suspension placed in the eye first
encounters mucin at the cornea & conjunctival surface .
 If polymers adheres to the mucin, the interaction is referred
as Mucoadhesion.
 Should exhibit a zero contact angle to allow maximum
contact with mucin coat .
 The capacity of polymer to adhere to the mucin coat
covering the conjunctiva and corneal surface of the eye non
covalent bond forms the basis of ocular mucoadhesion .
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 S.P. Vyas, Roop K.Khar ; Controlled Drug Delivery, concepts and
advances, Pg No: 383-410.
 Remington & Gennaro ; The Science & Practice Of Pharmacy. Mack
Publication Company. Easton, Pennsylvania. Pg. No. 1563-1567.
 International Journal of Pharmacy and Biological Sciences,2011,volume
2,Issue 4,Page No.437-446.
 N.K. Jain, Advances in Controlled and Novel drug delivery, page no.: 219
– 223.
 Y.W. Chein ,Novel drug delivery systems, published by Marcel Dekker,
vol.-50, page no. 269 – 301.
 www.vision-care-guide.com
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5 October 2016 Ocular Drug Delivery System presenter Sangram M. Patil
27

Ocular drug delivery system

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Ocular drug delivery system